4 gigabytes of RAM, yes but not on 32bits system
Don’t waste your money on 4 GB of RAM. You won’t be able to use it all with Windows XP or Vista 32bits…
"To address 4GB of memory you need 32 bits of address bus. (Assuming individual bytes are addressable.) This gives us a problem – the same problem that IBM faced when designing the original PC. You tend to want to have more than just memory in a computer – you need things like graphics cards and hard disks to be accessible to the computer in order for it to be able to use them. So just as the original PC had to carve up the 8086’s 1MB addressing range into memory (640K) and ‘other’ (384K), the same problem exists today if you want to fit memory and devices into a 32-bit address range: not all of the available 4GB of address space can be given over to memory."
Read this very nice blog entry giving even more details…
